This invention relates to a semiconductor light emitting device, a semiconductor light emitting apparatus, and a method of manufacturing a semiconductor light emitting device, and more particularly to a semiconductor light emitting device and a method of manufacturing the same in which the external light extraction efficiency is improved.
There is an increasing demand for higher brightness of semiconductor light emitting apparatuses in various applications such as backlights of liquid crystal displays, push button lamps of mobile phones, and lighting substituted for fluorescent lamps. In order to obtain high brightness while reducing power consumption, it is important to improve the external light extraction efficiency of a semiconductor light emitting device.
In a semiconductor light emitting device, the light emitted from its active layer can be extracted outside without multiple reflection only when the incident angle to the radiating surface is smaller than the critical angle. A semiconductor light emitting device having an radiating surface made of GaP (having a refractive index of about 3.3) and sealed in epoxy-based sealing resin (having a refractive index of about 1.5) has a critical angle of about 27 degrees. The light having an incident angle greater than the critical angle at the side face of the semiconductor light emitting device is either radiated outside after multiple reflection inside the device, or absorbed inside to result in ineffective light.
A structure for improving the external light extraction efficiency of a semiconductor light emitting device is disclosed in which the semiconductor light emitting device has an inclined side face to reduce the incident angle inside the device from the light emitting layer to the side face of the device, thereby reducing the influence of total reflection at the side face of the semiconductor light emitting device (e.g., Japanese Laid-Open Patent Application 2003-188410).